I had over 50 people in my house for a party last Christmas. Am I expected to know all of their criminal records? Some of them I only met within the last few years. What of ONE of them was a convicted fellon? I had an unsecured shotgun upstairs by my bed the entire time. Does that make me a potential criminal?
Owen, it would help you a lot to read the US Code on firearms transfers:
http://www.law.cornell.edu/uscode/html/uscode18/usc_sec_18_00000922----000-.html
The words, "know or have reasonable cause to believe" show up in most matters involving "
non-licensed" individuals. (Dealers are held to a higher standard.) If 50 people were at your house, and you don't know them all fairly closely, it is not reasonable to expect you to know that every one of them had a clean record, (and it sounds as though you were not providing them with firearms anyway).
Now,
could the matter make you a criminal? Sure. The possibilities are many and as varied as your imagination. Can a prosecutor establish to a jury's satisfaction that you did have reasonable cause to believe the neighbor you let shoot in your yard was a felon? Well, maybe. It would suck to have to pay the legal bill to fight it, successfully or not.
Is it
likely that you'll end up in court over an uneventful half-hour session of plinking -- even if the guy once was convicted of murder? No. So maybe the fact that you didn't inquire about his prison tattoo won't cause an issue. If you loaned him that gun and he later killed someone with it, well then you're going to spend some money on a lawyer.
Back to the Christmas party -- seems low-risk. You aren't deliberately supplying them with guns. The liklihood that you could be prosecuted because one felonious guest searched your closet and stole/accessed a firearm seem slim. Now change the scenario to an event where you're inviting those same 50 folks out to an afternoon of sporting clays or .22 plinking or whatever...you just might want to make some basic inquiries or work up a waiver or something. You're rolling those dice a bunch more times and shooting is a primary function of the event. A jury may believe it was "reasonable" for you to take some steps to ensure that you weren't handing a gun to any felons. Again, you might beat the rap, but not the legal fees.
Like so much of law, there is wrong, right, and then the vast expanse of grey area where guilt or innocence is going to depend on who can convince a jury of what. That's life.